package dyyx.simplerpc;

import java.util.List;

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.ByteToMessageDecoder;

public class RpcDecoder extends ByteToMessageDecoder {
    private Class<?> clazz;
    private Serializer serializer;
 
    public RpcDecoder(Class<?> clazz, Serializer serializer) {
        this.clazz = clazz;
        this.serializer = serializer;
    }
 
    @Override
    protected void decode(ChannelHandlerContext channelHandlerContext, ByteBuf byteBuf, List<Object> list) throws Exception {
        if (byteBuf.readableBytes() < 4) {
            return;
        }
 
        byteBuf.markReaderIndex();
        int dataLength = byteBuf.readInt();
        if (byteBuf.readableBytes() < dataLength) {
            byteBuf.resetReaderIndex();
            return;
        }
 
        byte[] data = new byte[dataLength];
        byteBuf.readBytes(data);
        Object obj = serializer.deserialize(clazz, data);
        list.add(obj);
    }
}
